Systems and methods for near band interference cancellation

Abstract

A method for self-interference canceller tuning for a near band radio includes receiving, in a first frequency band, an RF transmit signal of the near band radio; receiving, in a second frequency band, an RF receive signal of the near band radio; generating a self-interference cancellation signal from the RF transmit signal based on a set of configuration parameters; combining the self-interference cancellation signal with the RF receive signal to create a composite receive signal; and adapting the set of configuration parameters based on the compo-site receive signal.

We claim: 
     
       1. A method for self-interference canceller tuning for a near band radio comprising:
 receiving, in a first frequency band, an RF transmit signal of the near band radio; 
 receiving, in a second frequency band, an RF receive signal of the near band radio; 
 retuning a transmitter of the near band radio from the first frequency band to the second frequency band; 
 transmitting a weak signal on the second frequency band; 
 retuning the transmitter of the near band radio from the second frequency band to the first frequency band; 
 generating knowledge of a receive channel based on the weak signal; 
 generating a self-interference cancellation signal from the RF transmit signal based on a set of configuration parameters; wherein generating the self-interference cancellation signal comprises combining a set of filtered, scaled, and delayed versions of the RF transmit signal; 
 combining the self-interference cancellation signal with the RF receive signal to create a composite receive signal; and 
 adapting the set of configuration parameters based on the composite receive signal; wherein adapting the set of configuration parameters based on the composite receive signal comprises adapting scaling factors and delays; 
 wherein the first frequency band and second frequency band are non-identical. 
 
     
     
       2. The method of  claim 1 , wherein adapting the set of configuration parameters comprises adapting a set of complex weights and a set of delays. 
     
     
       3. The method of  claim 1 , wherein adapting the set of configuration parameters further comprises using a constrained optimization algorithm to adapt configuration parameters based on knowledge of transmit and receive channels of the near band radio. 
     
     
       4. The method of  claim 3 , further comprising performing transceiver retuning to generate the knowledge of transmit and receive channels. 
     
     
       5. The method of  claim 3 , wherein the constrained optimization algorithm is an alternating direction method of multipliers algorithm. 
     
     
       6. The method of  claim 1 , wherein adapting the set of configuration parameters further comprises estimating a self-interference channel from a ratio of receive and transmit channels and adapting the set of configuration parameters based on the estimated self-interference channel. 
     
     
       7. The method of  claim 6 , wherein estimating a self-interference channel from a ratio of receive and transmit channels comprises:
 measuring a first magnitude of the composite receive signal, wherein the first magnitude is measured for a first set of configuration parameters; 
 measuring a second magnitude of the composite receive signal, wherein the second magnitude is measured for a second set of configuration parameters; and 
 determining self-interference channel phase and magnitude from a difference of the first magnitude and the second magnitude and from a difference of the first set of configuration parameters and the second set of configuration parameters. 
 
     
     
       8. The method of  claim 7 , further comprising detecting that transmit signal noise is a dominant component of the composite receive signal. 
     
     
       9. The method of  claim 6 , wherein adapting the set of configuration parameters further comprises adapting the set of configuration parameters using a constrained optimization algorithm. 
     
     
       10. The method of  claim 1 , wherein the weak signal is a noise signal with known characteristics. 
     
     
       11. The method of  claim 1 , wherein retuning the transmitter comprises changing a local oscillator frequency of the transmitter. 
     
     
       12. The method of  claim 1 , wherein retuning the transmitter comprises changing a signal path of the transmitter.